a) Field of the Invention
The invention is directed to an electrical plug-in connector for electrical leads, particularly having a cable plug and chassis receptacle each having a housing with preferably flat contacts which contact one another when the plug-in connection is produced.
b) Description of the Related Art
According to the currently applicable EU regulations of the so-called Low-Voltage Directive, all plug-in connectors which carry peak voltages above a certain limiting value or which can effect currents above a determined threshold load resistance must be constructed so as to protect against electrical shock. This applies particularly, for example, to plug-in connectors which connect audio power amplifiers with loudspeakers. For example, insofar as such a power amplifier is capable of delivering more than 70 Watts to a loudspeaker with an impedance of 8 Ohms, the entire connection must be constructed so as to protect against electrical shock. A connection of this kind generally comprises a chassis-type receptacle at the amplifier and loudspeaker and a cable plug at both ends of the connection cable. Power plugs are not suitable, nor are they allowed, for this purpose because of the hazard of erroneous connection.
A low-voltage signal plug connector, especially for connecting amplifiers to loudspeakers must essentially have the following characteristics:
high reliability of contact PA1 high current-carrying capacity (up to 30 A) PA1 protected against electric shocks as currently prescribed PA1 noninterchangeable with other plug-in devices or nonreversible PA1 robust and economical PA1 enables simple and reliable locking of the cable plug in the chassis receptacle.
In this respect, reference is had to the arrangement for carrying and taking off current in installed apparatuses according to DE-PS 845 068. Current is supplied through current-conducting contact bars which are mounted so as to be isolated from one another such that they afford protection against electric shocks and are arranged in housings or strips comprising insulating material. Current is removed through springing or rigid contact faces which are arranged at the current take-off means such as handle parts, sockets or the like. The contact surfaces arranged at the current take-off means are mounted so as to be displaceable in the current-carrying contact bars. Known measures with respect to contact bars of this kind are not usable for electrical plug-in connectors and cannot be transferred to such electrical plug-in connectors.
DD-PS 141 380 further discloses a connection device for coupling with an identical connection device for an electrical connection. It comprises a frame part of insulating material which is arranged in a housing, wherein one end of the frame part is formed by a quantity of projecting fingers of electrically insulating material. Each of these fingers, with the exception of at least one, is provided, on the side facing the latter finger, with a contact member whose contact surface is smaller than the surface of the above-mentioned side. Intermediate spaces are arranged between each finger provided with a contact member and the finger toward which the contact member of such finger faces. The height of these intermediate spaces corresponds to the thickness of the fingers, so that the fingers of one connection device fit into the intermediate spaces of a complementing connection device. For this purpose, the contact members terminate at a distance from the free end of the respective finger, this distance being in a ratio to the height of the intermediate space such that the contact members cannot be touched by the user. The manner in which this connection device is to be realized in practice is not disclosed in this reference. This reference also does not show how the connection devices which are connected with one another could be mechanically locked with one another. Also, no specifics are given concerning the electrical cutoff protection whose function is to protect the current-loaded contact members from burning when the connection device is opened while carrying a current load.
U.S. Pat. No. 3,909,099 shows and describes an electrical connector with a cable clamp which is movably arranged at the connector. This cable clamp is freely pivotable in a plane containing the longitudinal axis of the cable, but is locked in its longitudinal direction. The contact elements arranged in the housing are swiveled slightly through the special support of the cable clamp during the manufacture of the electrically conducting plug-in connector. However, this reference does not point to a construction of a plug-in connector which satisfies the requirements listed above.